Explosion-proof enclosures are generally known for containing electrical equipment which is used in hazardous environments. Typically, the issue with hazardous environments is that a spark or flame could ignite flammable gasses or other constituents in the operating environment. Explosion proof enclosures are commonly used in hazardous locations in order to contain explosions that may occur within the enclosure and prevent sparks occurring within the enclosure from igniting vapors, gases, or other materials in the area surrounding the enclosure. Hazardous locations may include, for example, aircraft hangars, gasoline stations, paint finishing locations, agricultural areas, etc. Explosion-proof housings are designed and constructed to meet industry standards such as the explosion-proof standards contained in the National Electrical Code (NEC). Explosion proof enclosures often have conduits leading to them. Such conduits may carry cable or wiring, for example, to power circuit protection or control equipment for machinery outside the enclosure, such as a motor or a compressor.
The National Electric Code (NEC®) defines classes and divisions of hazardous locations, as well as requirements for explosion proof enclosures used in such locations. For example, a Class I hazardous location or area is one in which flammable gases or vapors are/could become present in concentrations suitable to produce explosive and/or ignitable mixtures. A typical class I area is a petroleum processing facility, for example. Within Class I, a Division 1 area or location includes: one where the atmosphere of the area is expected to contain explosive mixtures of gases, vapors or liquids during normal working operations; one where ignitable concentrations frequently exist because of repair or maintenance operations; or one where there is release of ignitable concentrations of gases or vapors due to equipment breakdown, while at the same time causing electrical equipment failure. A Class I, Division 2 hazardous location includes: one where flammable liquids or gases are handled, but not expected to be in explosive concentrations, with the possibility of explosive concentrations resulting from an accidental rupture or other unexpected incident; one where ignitable gases or vapors are normally prevented from accumulating by positive mechanical ventilation, but could exist in ignitable quantities if there is a failure in the ventilation system; and areas adjacent to Class I, Division 1 locations where it is possible for ignitable concentrations of gas/vapors to enter the area due to lack of proper ventilation.
Explosion-proof installations are highly regulated and are subject to inspection to ensure compliance with the pertinent regulations and standards. In this regard, there is a need for facilitating the inspection process with respect to explosion-proof installations. There is also a general need for reducing the complexity, part count and cost of explosion-proof enclosures.